arm-cci: Fix CCI PMU event validation

We mask the event with the CCI_PMU_EVENT_MASK, before passing
the config to pmu_validate_hw_event(), which causes extra bits
to be ignored and qualifies an invalid event code as valid.

e.g,
 $ perf stat -a -C 0 -e CCI_400/config=0x1ff,name=cycles/ sleep 1
   Performance counter stats for 'system wide':

         506951142      cycles

       1.013879626 seconds time elapsed

where, cycles has an event coding of 0xff. This patch also removes
the unnecessary 'event' mask in pmu_write_register, since the config_base
is set by the pmu code after the event is validated.

Acked-by: Punit Agrawal <punit.agrawal@arm.com>
Reviewed-by: Will Deacon <will.deacon@arm.com>
Signed-off-by: Suzuki K. Poulose <suzuki.poulose@arm.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>

1 files changed, 7 insertions, 5 deletions

diff --git a/drivers/bus/arm-cci.c b/drivers/bus/arm-cci.c
index 054df84562c2..b854125e4831 100644
--- a/drivers/bus/arm-cci.c
+++ b/drivers/bus/arm-cci.c
@@ -81,7 +81,7 @@ static const struct of_device_id arm_cci_matches[] = {
 
 #define CCI_PMU_CNTR_MASK       ((1ULL << 32) -1)
 
-#define CCI_PMU_EVENT_MASK              0xff
+#define CCI_PMU_EVENT_MASK              0xffUL
 #define CCI_PMU_EVENT_SOURCE(event)     ((event >> 5) & 0x7)
 #define CCI_PMU_EVENT_CODE(event)       (event & 0x1f)
 
@@ -179,12 +179,15 @@ enum cci400_perf_events {
 #define CCI_REV_R1_MASTER_PORT_MIN_EV   0x00
 #define CCI_REV_R1_MASTER_PORT_MAX_EV   0x11
 
-static int pmu_validate_hw_event(u8 hw_event)
+static int pmu_validate_hw_event(unsigned long hw_event)
 {
         u8 ev_source = CCI_PMU_EVENT_SOURCE(hw_event);
         u8 ev_code = CCI_PMU_EVENT_CODE(hw_event);
         int if_type;
 
+        if (hw_event & ~CCI_PMU_EVENT_MASK)
+                return -ENOENT;
+
         switch (ev_source) {
         case CCI_PORT_S0:
         case CCI_PORT_S1:
@@ -258,7 +261,6 @@ static void pmu_enable_counter(int idx)
 
 static void pmu_set_event(int idx, unsigned long event)
 {
-        event &= CCI_PMU_EVENT_MASK;
         pmu_write_register(event, idx, CCI_PMU_EVT_SEL);
 }
 
@@ -275,7 +277,7 @@ static int pmu_get_event_idx(struct cci_pmu_hw_events *hw, struct perf_event *ev
 {
         struct cci_pmu *cci_pmu = to_cci_pmu(event->pmu);
         struct hw_perf_event *hw_event = &event->hw;
-        unsigned long cci_event = hw_event->config_base & CCI_PMU_EVENT_MASK;
+        unsigned long cci_event = hw_event->config_base;
         int idx;
 
         if (cci_event == CCI_PMU_CYCLES) {
@@ -296,7 +298,7 @@ static int pmu_get_event_idx(struct cci_pmu_hw_events *hw, struct perf_event *ev
 static int pmu_map_event(struct perf_event *event)
 {
         int mapping;
-        u8 config = event->attr.config & CCI_PMU_EVENT_MASK;
+        unsigned long config = event->attr.config;
 
         if (event->attr.type < PERF_TYPE_MAX)
                 return -ENOENT;